>> Also, your filesystem should have been created after
>> create-md, on the /dev/drbdX device (unless I'm gravely
>> mistaken).
>> Yes, that makes sense, but I was mainly trying to illustrate that it was
> specifically the create-md function that "did something" to the disk to
> make it unmountable.
I take this as a sign that you have damaged your fs with that create-md.
You should not use this disk in production as is.
>> In any case, the fs has no notion of DRBD
>> whatsoever, as DRBD works on the block layer of things.
>> That's what I would've expected, too, but apparently having the meta data
> at the end is enough to confuse mount's automatic filesystem detection.
I'm not at all familiar with ext4, but this does seem very strange,
especially seeing as it can be mounted when giving the specific type.
I'd be grateful if someone could shed some additional light on this
phenomenon.
Thanks,
Felix